Here's a tip. You will probably need to remove the brake part and clean them before you can adjust as the 2 dowel pins tend to rust and not move properly. It's not very difficult.

I would remove the adjustment nut and brake arm. Remove the 2 dowel pins. Remove the 2 screws holding the brake puck housing to the gearbox. NOTE: there is a metal plate behind the brake puck with the dowel pins. DO NOT loose the metal plate and make sure it is installed when you reassemble. If not the 2 dowel pins will break the puck. DO NOT remove the brake disc unless you need to replace the puck.

With the dowel pins and metal plate/puck out you can use some steel wool wrapped around a small drill bit to clean the inner dowel pin holes. Just use a drill and run the steel wool through the holes a couple of times to clean.

Clean the both dowel pins with steel wool or a wire brush. The should not be any rust. Once all parts are clean, intall metal plate NEXT to dowel pin holes, then the puck and bolt the
brake puck housing back on the gear box.

LIGHTLY grease the dowel pins with some white grease...just a little to keep them from rusting as well as the arm where it contacts the dowel pins.

Install dowel pins, brake arm and the nut. Set the parking brake. Adjust the nut until the mower can not roll with the brake set. Release brake and see if the mower rolls easy. You will have to set the brake, adjust, roll a few times to get the proper setting.

Experience

Born and raised in the midwest. Started tinkering with engines when I was about 14 on my Suzuki RM-80. I began lawn mower repair at a small hardware store. I knew absolutely nothing. I read lots of repair manuals and met an older fellow who taught me many lessons. I continued working on small engines through high school and paid my way through college working on mowers at the same hardware store. Decided to get away from the midwest and mower repair so I joined the Air Force. I repaired air traffic control electronic equipment and ended up in Hawaii where I got a part time job at Small Engine Clinic. I gained a lot of experience from the Small Engine Clinic and had a blast repairing small engines. I then took the Briggs and Stratton Master Service Technician test and earned my MST. I then traveled to Wisconsin where I attended the factory update training seminar and received formal training. Continued working on mowers part time as I completed 20 years of military. Retired from the military on a Friday and continued in the lawn and garden industry the next Monday.